The AntiRice

hey all, i have kind of a technical question that i need to get an answer on. Over this weekend me and a friend installed a JRSC on my 2k Si and right now the only 2 guages i have is an autometer a/f (iknow i know) and a boost guage, and a vafc which is not installed yet. I have a dyno appt this friday comming up. Heres my question. in the jackson manual in the fuel inrichment relay install step it says a few things that are not correct, onebeing the color of the wire that needs to be hooked up off the distributor to power the relay, it says yellow with a black stripe and its actually black with a yellow stripe. anyways, the relay is hooked up according to the manual but every so often looking at the a/f guage it does not go into right when you floor it, it only pegs in the middle orange area, like its not dumping in the fuel. The relay hookes up to a tab on the top of the manifold, and to switched power, and it interrupts the intake air temp sensor at the plug. my question is, does it matter which wire goes to what side on the iat because it runs through a relay that has a small capacitor on it and the instructions dont say one way or the other. My other guess is there is a bad connection on the wire comming from the o2 sensor but the guage still works just shows up funny. like sometimes when just driving normally it only bounces from lean to the middle and other times it will bounce from lean all the way over to rich. when it only bounces from lean to the middle is when it doesnt show that its going ritch when you floor it. I know the dyno will show us if it is actually the guage or the relay setup, but i dont wanna get there and be screwed outta the money becuase there is something wrong with the install side of it any help anyone can give would be good at this point . thanks in advance
-Brian

zip

Don't attach the relay on the manifold since the vibration from the engine will cause erratic operation. Just zip-tie the relay to the firewall. It doesn't matter which red/yellow wire you attach from the IAT. The AF gauge should directly go to very rich at wide open throttle. If it's stays in stoich, or orange, get off the throttle since there's something wrong with the relay or fuel delivery. The AF gauge will bounce back and forth at idle and during part throttle cruising. If the car hesitates at WOT check you fuel pressure settings by following the steps below:

The JR FMU rise rate is fixed at 5:1 However, the static fuel pressure is kind of adjustable. Here's a repost on the "how to" I posted a while back to give you an idea on its adjustability.

How to adjust the JR FMU question arises every couple of months when a new owner wants to lean out the overly rich setting of the JR FMU. To adjust the FMU, its mandatory you have at least a mechanical fuel pressure guage and a rudimentary A/F ratio guage. The fp guage enables you to set the fuel pressure precisely and the a/f guage will determine if you've leaned out the max fuel pressure too much at WOT. Make sure you have the engine warmed up and have done at least one, full boost run. The reason you need a full boost run is because the JR FMU diaphram is inconsistent when you haven't boosted for a long time (in my case anyway).

Here are the basic tools you need:


This is my idle fuel pressure (it's a bit high), yours may vary.


To adjust the static fuel pressure:
Have the engine running while you perform the adjusments and make sure you don't drop anything near the belts or the radiator fan!

First, locate the jam nut and set screw behind the JR FMU


Second, loosen the jam nut (turn counterclockwise)


Take the vacuum hose off the JR FMU and plug it with a golf tee, or anything similar, to keep the engine idling correctly.


To adjust the static pressure turn the set screw (clockswise=raise fuel pressure, counterclockwise=lessen fuel pressure) w/ an allen wrench.


After you have set the proper fuel pressures for your setup, reinstall the vacuum line and tighten the jam nut (clockwise). That's it!

Make sure you have the vac line clamped to the JR FMU because the boost pressure may cause the hose to pop loose. Your vac line is the lifeblood of your motor, if it comes loose at WOT say goodbye to your motor!

The ballpark static fuel pressures for 7-8lbs of boost is ~55-58psi, 8-10lbs is ~58-62psi. These fuel pressures will vary according to climate and altitude. This is why you need an a/f meter to determine if your running rich at WOT.

The AntiRice

cool zip, ya i saw that post in got boost? on club si but heres the thing. when i did what your instructions say, capped off the line with a golf tee and adjusted the static fuel pressure to approx 55 psi its fine but then when i put the line back on the fmu, it only shows approx 10 psi lower than what it was set on with the golf tee in the line. could that mean a vacuum leak of some sort? i mean its about a 6 or 8 inch hose from the manifold any idea or is that how its supposed to work? i took it for a test run after setting it to 55 psi with the tee in but like i said when i attach the line back to it, it drops off. TIA


-Brian

zip

That's normal, the vacuum of the engine will cause the fuel pressure to read 10 or more psi lower than static. As the engine reaches atmosphere the fuel pressure will increase. If you have a fuel pressure gauge you can see the pressure ramping up prior to boost. The specs for the Si is 31-37psi at idle. The high flow fuel pumps will cause the fuel pressure to rise above stock, so buying a B&M fpr hack, AEM fpr, drilling a relief hole on the fpr will help lower idle fuel pressure, preserve off-boost drivability, and preserve fuel economy. Make sure the static pressure is preserved when you lower the idle fp with an adjustable fpr.

The AntiRice

i have a b&m FPR already, thats set cool no problem as far as i can tell. i talked to my friend that helped me install the kit and he said basically what you said, that its fine and its supposed to drop off i wasnt thinking that by capping off the line that is setting the max pressure under full boost. do you know exactly how that relay is supposed to work? from what i could gather with a meter the tab on the charger rests at ground and goes away from ground on boost, but should the relay click on under boost or what happens there? if i had someone sit in the car and blip the throttle should the relay click on or is it normally only at WOT that it needs to dump in more fuel? Sorry for so many questions its just not to many people would know these things off hand and if i call jackson my guess is they will blame the guage or something else. TIA

zip

The relay is ON when the key is in the ONII position or when the engine is started. The pressure switch cuts off the ground when the pressure is above 1psi of boost causing the ECU to richen fuel due to the lower temperature reading given off by the IAT hack.

The link below is more JRSC friendly than this board and has a lot of archived info on JR installs:
http://www.hostboard.com/cgi-bin/for...100&LastLogin=

Count Blah

zip-

(whats up its Todd (FBP Civic Si - lunch at chevys with sonny )

Hey the problem we are having is not setting the fuel pressure (or so i think) but its the following, i think due to the relay not working, or the FMU not being consistent.

Certain times, random in occurance, the a/f gauge will not make full sweep passes during normal driving conditions, it bounces between lean and stoich, never hitting the rich indicators. When @ WOT under those conditions, the a/f will not go past stioch, all 5 or 6 orange bars are lit up (we have only done this a few times so hopefully no damage has occured)

Other times, also random in occurance, the a/f gauge will make full sweep passes during normal driving conditions, bouncing between all the way lean and all the way rich, which leads me to believe normal operation. When @ WOT there, the a/f will stay pegged at rich.

So i guess my/our question really is - why is the fuel ratio so inconsistent? Could it be the gauge is not functioning correctly, the relay not working to richen the mixture, the FMU not richening the mixture (no in cabin FP gauge yet...).

Any suggesstions?

-Todd

zip

Hey Tdiddy, I think it's the relay malfunctioning while the engine is moving. Place the relay on the firewall as I stated above to resolve vibration caused erratic operation. To check if the relay is working, place the key on the ONII position and remove the ground tab from the pressure switch. The relay should make an audible click everytime you touch a ground source. Also, make sure the 15K resistor is securely fastened. If you have an ohmeter measure the resistance between the red/yellow wire while the relay is ungrounded and measure the resistance. It should read 15kilohms.

To make sure the relay is working correctly, remove the ground tab and insulate it w/ some electrical tape so it doesn't ground itself. Make a WOT run under boost and verify if the AF is pegged rich, or if there is any hesitation.

If the AF is pegged rich under WOT then everything is fine and the relay is intermittently working due to it's position on the manifold. If the AF is pegged in the stoich area, then something is wrong with the fuel delivery or the AF isn't connected correctly. BTW, the AF will not reach full rich all the time during closed loop if the AC is on, or if there is any load substancial load to the alternator, i.e. headlights, stereo, etc. But the AF should always be reading rich under WOT. Good luck.

The AntiRice

ok, this is gonna confuse the f out of you. My guess is the guage is hooked up incorrectly, i dont see how this is even possible but check out my process of elimination. ok so i went outside and tried a few things. 1: double verified the FMU is set correctly, is it. 2: pulled the wire off the manifold with the engine running and my other hand on the relay and sure enough "click", relay working. noticed the a/f guage is running full sweep side to side as it should be so i hop in and am going to go around the block and tryit out. its dark out so obviously i turn on my lights and pull away, boost a litle guage pegs in the stoich again. **** turn around go home, pull in the driveway guage only sweeping on the left to center. turn off the lights and about so switch off the car and notice the guage is sweeping all the way normally. So im totaly confused so i turn on the lights and the guage reads only left to center. So i back out of the driveway and go down the road to a empty area, turn off the lights and boost in 1st sure enough, pegged in green (rich) Stop turn on lights do same little run guage only reads in the middle (stoich) so somehow im guessing the guage is hooked up incorrectly, unless you think otherwise? Ill have to go in and check my connection for power on the guage thats all i can gather. Im just overly concerned becuause i have to drive the car untill friday till my dyno appt. any thoughts or suggestions on this? BTW I tried that link it wasnt working for me! TIA

-Brian

The AntiRice

ok, i may have solved my own problem (with your help of coarse) im pretty sure its the guage in hooked up incorrectly. earlier in the day when it was working properly it was daytime, thus lights were not on. Now that i think about it the guage reads funny only when the lights are on (i think) as proved by what i just went out and did. I installed the guage to power and ground over 2 months ago but never hooked up the sensor wire untill yesterday when we put in the JRSC so it would never have worked untill now anyways. I cant remember what its hooked up to but ill have to go in and use a different source for power and ground and see how that works. i apreciate your help 200 times over but i cross my fingers that i am just an idiot and the guage is hooked up wrong. i will try this tomorrow AM and see what happens. thanks again zip you rule

-Brian

Count Blah

Brian i can vouch for that idiot part, but i still hope the a/f is right

JK buddy

-Todd

2kbill

More info on wiring the A/F gauge:
http://www.hostboard.com/ubb/Forum40/HTML/008898.html

-and-

http://www.hostboard.com/ubb/Forum40/HTML/008318.html

HTH,
Bill